Aircraft Accident/Incident Report

Nikiski, Alaska 99635
Friday, April 21, 2006 1:06 AKD

NTSB Narrative Summary Released at Completion of Accident

The airline transport certificated pilot was transporting an Alaska State Trooper, and a rescue volunteer with their equipment, to a remote lodge to search for a missing person. The flight was conducted during dark night conditions, and the pilot was using night vision goggles (NVG) to help discern topographical features on the snow-covered terrain. After an uneventful outbound flight to the lodge, the pilot landed the helicopter on a frozen lake adjacent to the lodge. During an hour-long search of the lodge and surrounding outbuildings, snow fell, with a light accumulation on the frozen lake where the accident helicopter was parked. Unable to locate the missing person, the search team boarded the helicopter for the return flight, and the pilot donned his NVGs. Just after takeoff, as the helicopter transitioned from a hover to forward flight, blowing snow from the helicopter's main rotor momentarily reduced the pilot's visibility, and he lost all visual reference with the surface of the frozen lake. While he was attempting to regain a visual reference, the helicopter's tail rotor guard and vertical stabilizer struck the surface of the lake, and he elected to abort the takeoff. The helicopter's skids subsequently struck the surface of the ice, and the helicopter bounced several times before stopping. A postaccident inspection revealed substantial damage to the helicopter's vertical stabilizer, tail boom assembly, and fuselage. The pilot reported that there were no preaccident mechanical anomalies with the helicopter, and that he had not received any formal training in the use of NVG's.

NTSB Probable Cause Narrative

The pilot's failure to maintain adequate altitude/clearance from terrain during an aborted takeoff in whiteout conditions, which resulted in an in-flight collision with terrain. A factor associated with the accident was whiteout conditions.

Event Information

Type of Event Accident
Event Date 4/21/2006
Event Day of the Week Friday
Time of Event 106
Event Time Zone --
Event City Nikiski
Event State ALASKA
Event Country --
Zipcode of the event site 99635
Event Date Year 2006
Event Date Month 4
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 612559N
Event Location Longitude 1513841W
Event Location Airport --
Event Location Nearest Airport ID --
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness --
Investigator's weather source Pilot
Time of the weather observation
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID --
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions Night
Lowest Ceiling Height 800
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 2
Air Temperature at event time (in degrees celsius) 30
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) --
Variable Wind Indicator --
Wind Speed (knots) --
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 3
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 21260
NTSB Notification Source ANC FAA, ROC
NTSB Notification Date Apr 21 2006 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Apr 25 2007 2:54PM
User who most recently changed record NTSB\lema
Basic weather conditions Visual Meteorological Cond
FAA District Office Anchorage FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N911AA
NTSB Number ANC06TA047
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed Company VFR
Flight plan Was Activated? Yes
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name American Eurocopter
Aircraft Model AS350 B3
Aircraft Series Identifier --
Aircraft Serial Number 3611
Certified Max Gross Weight 4961
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 6
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Mar 1 2006 12:00AM
Airframe hours since last inspection 29.2
Airframe Hours 967.6
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name State of Alaska, Department of Public Safety
Aircraft Owner Street Address 4827 Aircraft Drive
Aircraft Owner City Anchorage
Aircraft Owner State AK
Aircraft Owner Country USA
Aircraft Owner Zipcode 99502
Operator is an individual? No
Operator Name --
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City --
Operator State --
Operator Country --
Operator Zip code --
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Public Use
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code --
Departure City Nikiski
Departure State AK
Departure Country USA
Departure Time 106
Departure Time Zone ADT
Destination Same as Local Flt --
Destination Airport Code --
Destination City Soldotna
Destination State AK
Destination Country USA
Specific Phase of Flight Takeoff
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Oct 31 2007 1:07PM
User who most recently changed record NTSB\HAMG
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --